lord of Tyrconnell, Irish chieftain of the O'Donnells.

Son of Manus O'Donnell and half brother of Calvagh O'Donnell, he at first allied himself with the O'Neills in his family feud with Calvagh (1557); but he then turned round and combined with the English to crush the O'Neills, the hereditary enemy of his family. In 1567 he utterly routed Shane O'Neill at Letterkenny with the loss of 1,300 men, compelling O'Neill to seek refuge with the MacDonnells of Antrim, by whom he was treacherously put to death. In 1592 Hugh abdicated in favour of his son Hugh Roe O'Donnell (O'Donnell, Hugh Roe) (q.v.).